Dear all,
today the engine of my Double Six stopped suddenly when I was doing a road test.
This morning I have changed the sparks plugs, HT leads, distributor cap (Lucas for the avoidance of any doubt), rotor and air filters. Everything was made with no issues and the car started perfectly and running very smoothy, better than before (I previously had a misfire on b-Bank and it disappeared after the service).
I went for a road test and the car was driving perfect. After 15 kms on the highway I filled one tank and came back home. I was driving quite fast (ca. 160 km/H) and suddenly the tacho went down to zero. I could not believe that the engine had stopped, but it had. I parked and it do not start on the first attempts. I had to wait ca. five or ten minutes and then it started again. I drove it home normally.

Any idea of what maybe the cause?

Something similar happened when I bought the car, but in that case it started inmediately. I thought it was due to some dirt in the right tank, which I still have not cleaned. This time I was driving with that one, which was the one I have filled (what always removes dirt), but it should have started after connecting the other tank.

Thanks in advance for any help,
José

 

Instant death 99% of the time is electrical, lost the tacho you lost the signal which comes from the amplifier, if you said it restarted immediately I'd go after the main relays / ignition switch but since you indicated a cool down delay was required I'd say this whilst possible is unlikely.

Do you have the vacuum connected via the distrubutor cap ? - small detail but that's how the trigger module keeps cool. Sounds like something is getting hot if you touched nothing and it restarted after some time off, will be hard to nail down, I'd be opening up the ignition amp, make sure the condenser is removed and also replace the thermal compound below the module with some more modern stuff - one of those used for PC building such as Arctic Silver work well - this stuff does degrade over time becoming less and less effective.

 

This sounds exactly like what my car did last weekend, although mine would restart after 1 minute, maybe 30 seconds. I’ve replaced some components and some broken wires, but I haven’t tested it thoroughly yet.

 

That is almost certainly the Lucas amplifier on the top of B bank inlet manifold failing as it gets hot. A new one from Manners is a very sensible purchase.

 

Mine is a Marelli car but I had the same (sounds much the same) happen to me this past Saturday morning. driving, doing about 70mph, rmps wanted to drop to zero, car felt as if it would stall, then it came back to life. Happened twice within a couple of minutes of each event. Very hot 96 degrees out...

I did slowly drive her back home, about 15miles, some highway and it didnt happen again... I parked her... Don't know what the problem was or what I am going to do yet... Never actually stalled fully,,, but I cant trust to drive it again until I get it figured, which doesn't seem like its going to be easy - unless it stalls completely and doesn't come back. Intermittent problems like this are no no fun!

 

That's my gut feeling as well....although the 'could be' list can become quite long with this type of problem!

More specifically, the D1906 Delco ignition module inside the amplifier. These are notorious for giving trouble after absorbing heat....and returning to normal operation after a cool-down.

The module can be replaced easily enough....but might not be readily available in all parts of the world.

Cheers
DD

 

Thanks for all your answers. Today it was even worse. It stopped after a short drive, started after five minutes, off again…. The Lucas amplifier was extremely hot, but it always was hot before.
@BenKenobi I do have the vacuum connected to the distribution cap. I have checked both, but I think mine has no trigger board.
There must be a link between the new cap, HT leads, etc and this failure; it cannot be a coincidence. It had never happened
@Greg in France Do you recommend the amplifier sold by Manners better than the one offered by SNG Barrat?

 

Has happened on my Lucas convertible. It was a hot day, about 42degC, and had driven 200km that day. Engine suddenly stopped while cruising along at 70kmh. Opened the bonnet, poured a little cold water onto the ignition amp. Waited 2 minutes, started engine and no more trouble that day. The Delco modules are not so expensive and generally reliable. Other brands have a bad reputation when used on a V12.

 

I have one from Manners, to cure a similar problem, and it is fine. There are a couple of models, the only difference being the connector to the white wire. Buy the cheaper and fix a new connector is what I did. I think you will find they are all made by the same people.